U.S. patent number 7,281,790 [Application Number 10/986,911] was granted by the patent office on 2007-10-16 for ink-jet recording method and ink-jet recording apparatus.
This patent grant is currently assigned to Canon Kabushiki Kaisha. Invention is credited to Akihiro Mouri, Hiroshi Taniuchi.
United States Patent |
7,281,790 |
Mouri , et al. |
October 16, 2007 |
**Please see images for:
( Certificate of Correction ) ** |
Ink-jet recording method and ink-jet recording apparatus
Abstract
An ink-jet recording method and an ink-jet recording apparatus,
wherein ink image with high quality and good abrasion resistance
without generation of beading and bleeding are formed on recording
media, in ink-jet recording using an intermediate transfer body,
are provided. An ink image is formed by applying an image fixing
component (for example reacting liquid) to an intermediate transfer
body, and then applying inks of colors, Y, M, C, and K, from print
heads corresponding each color. Then a supplementary liquid is
applied to the ink image, and the ink image is transferred to a
recording media.
Inventors: |
Mouri; Akihiro (Tokyo,
JP), Taniuchi; Hiroshi (Kanagawa, JP) |
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JP)
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Family
ID: |
34593984 |
Appl.
No.: |
10/986,911 |
Filed: |
November 15, 2004 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050110856 A1 |
May 26, 2005 |
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Foreign Application Priority Data
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Nov 20, 2003 [JP] |
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2003-391485 |
Oct 21, 2004 [JP] |
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2004-307229 |
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Current U.S.
Class: |
347/103;
347/102 |
Current CPC
Class: |
B41J
2/0057 (20130101); B41M 5/0017 (20130101); B41M
5/0256 (20130101) |
Current International
Class: |
B41J
2/01 (20060101) |
Field of
Search: |
;347/103,101,102 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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62035848 |
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Feb 1987 |
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JP |
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62-92849 |
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Apr 1987 |
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JP |
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1-146750 |
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Jun 1989 |
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JP |
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5-200999 |
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Aug 1993 |
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JP |
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7-89067 |
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Apr 1995 |
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JP |
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7-256873 |
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Oct 1995 |
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JP |
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11-188858 |
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Jul 1999 |
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JP |
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Primary Examiner: Meier; Stephen
Assistant Examiner: Tran; Ly T.
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper &
Scinto
Claims
What is claimed is:
1. An ink-jet recording method comprising the steps of: applying a
first material that reduces flowability of ink having colorants, to
an intermediate transfer body; forming an ink image on said
intermediate transfer body by applying said ink from a print head
to said intermediate transfer body to which said first material has
been applied; transferring said ink image formed on said
intermediate transfer body to a recording medium; and applying a
second material to improve abrasion resistance of images on said
recording medium to said intermediate transfer body before said
transferring step.
2. An ink-jet recording method comprising the steps of: applying a
first material for making colorants of ink coagulate, to an
intermediate transfer body; forming an ink image on said
intermediate transfer body by applying said ink from a print head
to said intermediate transfer body to which said first material has
been applied; transferring said ink image formed on said
intermediate transfer body to a recording medium; and applying a
second material having resin to said intermediate transfer body
before said transferring step.
3. An ink-jet recording method as claimed in claim 2, wherein said
first material is a liquid at least having a metal salt.
4. An ink-jet recording method as claimed in claim 2, wherein said
second material is a liquid at least having a water-soluble
resin.
5. An ink-jet recording method as claimed in claim 2, wherein said
colorant is a pigment.
6. An ink-jet recording method as claimed in claim 2, further
comprising a drying step of drying said ink image prior to said
transferring step.
7. An ink-jet recording method as claimed in claim 2, further
comprising a cleaning step of cleaning said intermediate transfer
body after said transferring step.
8. An ink-jet recording method as claimed in claim 2, wherein a
surface of said intermediate transfer body includes a compound at
least having fluorine or silicone.
9. An ink-jet recording method as claimed in claim 2, wherein said
second material applying step applies said second material to said
intermediate transfer body by means of a roller or a print
head.
10. An ink-jet recording method as claimed in claim 2, wherein said
second material applying step is performed after said ink applying
step.
11. An ink-jet recording method as claimed in claim 2, wherein said
second material applying step is performed after said first
material applying step and before said ink applying step.
12. An ink-jet recording apparatus comprising: first application
means for applying a first material that reduces flowability of ink
having colorants, to an intermediate transfer body; formation means
for forming an ink image on said intermediate transfer body by
applying said ink from a print head to said intermediate transfer
body to which said first material has been applied; transfer means
for transferring said ink image formed on said intermediate
transfer body to a recording medium; and second application means
for applying a second material to improve abrasion resistance of
images on said recording media medium to said intermediate transfer
body before the ink image is transferred by said transfer
means.
13. An ink-jet recording apparatus comprising: a first application
portion that applies a first material for rendering colorants of
ink coagulate, to an intermediate transfer body; a formation
portion that forms an ink image on said intermediate transfer body
by applying said ink from a print head to said intermediate
transfer body to which said first material has been applied; a
transfer portion that transfers said ink image formed on said
intermediate transfer body to a recording medium; and a second
application portion that applies a second material having resin to
said intermediate transfer body before the ink image is transferred
in said transfer portion.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink-jet recording method and an
ink-jet recording apparatus, and more precisely relates to an
ink-jet recording method and an ink-jet recording apparatus for
recording by forming an ink image on an intermediate transfer body,
and transferring the ink image to an recording medium.
2. Description of the Related Art
The ink-jet recording system, electrophotographic system, thermal
head system, dot impact system and the like are currently utilized
as recording systems for image recording apparatuses that record
and output in response to the request of users the images made by
computers, duplicate images of printed matters, and facsimile
images.
Among the systems, the ink-jet recording system is a quiet printing
system that prints letters and images by directly ejecting the ink
onto materials for printing (recording media) such as paper, cloth,
plastic sheets, etc. in response to image signals. Since this
system does not require any complicated apparatus, its running cost
is low and it is easily downsized and colorized. The system is
further variously advantageous, for example, in flexibility towards
size of recording media from card size to large poster size. In
terms of quality of images also, output of images with quality as
high as that of silver salt color photographs has become possible
in recent years. Since recording apparatuses utilizing the ink-jet
system are advantageous as described above, they are used not only
for printers as output apparatuses connected to personal computers
but also as output apparatuses for office automation machines such
as facsimiles and copy machines. Further, the systems are also
widely used in the field of industrial production for printing
various cards, packages and large-size posters.
As a recent trend in various fields, there is a demand for
outputting high quality images by means of ink-jet recording system
regardless of kinds of recording media. In order to meet such a
demand, especially in these cases, factors or phenomena such as
"feathering", "beading", and "bleeding" that cause deterioration of
images on recording media as described later need to be controlled.
These phenomena have become more pronounced as ink-jet recording
becomes faster.
The above-mentioned phenomena that cause deterioration of images
are closely related with characteristics of recording media and
properties of inks for recording. In the case of forming images on
recording media formed with cellulosic fiber, such as regular paper
(PPC), by ejecting inks, for example, "feathering" phenomenon or
exudation of ink along the fiber comprising the recording media
unless the inks or the recording media are provided with any
chemical treatment. In the case of forming images on non-absorbing
recording media comprised of plastic sheets such as PET
(polyethylene terephthalate) and polyethylene that reject
infiltration of solvents, or on gloss printing paper that allow
only a little infiltration of inks, a phenomenon called "repelling"
occurs in which inks ejected onto the recording media are not
completely absorbed and flow. At the same time, the ink dots that
are formed on the recording media gather together and neighboring
ink dots get mixed, resulting in the phenomenon of "beading".
Further, overlapped colors exude to each other at their boundary,
resulting in the phenomenon of "bleeding" and deterioration of
quality of image formation. Therefore, it has been difficult to
form good images on regular paper or non-absorbing recording media
by means of an ink-jet recording system.
As the method for solving the above-mentioned problems, ink-jet
recording using inks that are made to fit various recording media
by changing solvents in ink compositions or causing liquid-solid
phase changes is known. Here, the main solvents of recording inks
are classified as oil-based, organic solvent-based and water-based
solvents. Generally, when oil-based and organic solvent-based inks
are used, the apparatuses need to be provided with exhaust and
recovery systems to avoid odor and influence to environment and
human bodies, resulting in the problem that the apparatuses become
larger. Further, rapid evaporation of the solvents tends to cause
clogging of nozzles of the print head which are ejection port.
Therefore, it is not advantageous to use oil-based and organic
solvent-based inks for recording. Water-based inks, on the other
hand, do not require consideration of influence to environment and
human bodies in conformation of apparatuses, since tasteless,
odorless, and colorless water is used as the solvent. Also,
water-based inks are free from clogging of nozzles by inks and are
widely used.
There is a recording system called a hot melt ink-jet system that
utilizes liquid-solid phase change. When this system is used, the
inks are heated to become less viscous and either ejected directly
onto recording media or ejected onto heated intermediate transfer
body for formation of ink images. The ink images are then
transferred from the transfer body to recording media to form
images. In either case, the inks are solidified by spontaneous
cooling on recording media to form images. Such a hot melt system
has an advantage that recording on any recording media is
possible.
This system, however, requires exertion of liquid-solid phase
change characteristics of inks. This results in increase in amounts
of resin which shows liquid-solid phase change characteristics much
more than colorants, and requires large amount of inks on recording
media in order to obtain desired optical concentration. As a
result, there has been a problem of deterioration of quality of
images due to thickness of inks deposited on the recording media.
Further, since solid inks need to be once melted to make liquid, it
is necessary to keep the ink supply routes and print heads heated
during operation of the apparatus and to always maintain the ink
onto liquid states, causing consumption of enormous amount of
energy. The system is not useful from the view point of energy
saving either.
Many of other known recording systems that intend to solve the
above-mentioned problems propose so-called transfer systems that
once form ink images on an intermediate transfer body by means of
an ink-jet recording system, increase the viscosity of the ink
images on the intermediate transfer body through drying of the ink
or remove of the solvent from the ink images to concentrate the
ink, and then transfer the ink images from the intermediate
transfer body to the recording media (U.S. Pat. No. 4,538,156, U.S.
Pat. No. 5,099,256, and Japanese Patent Application Laid-open No.
62-092849(1987)). The recording methods of these transfer systems
are not methods of forming images on recording media through
infiltration of water in the ink into the recording media as in the
conventional ink-jet recording systems. Therefore, they are
effective means especially for preventing feathering phenomenon in
which inks spread along fibers of a recording media while the inks
infiltrate into the recording media. Further, it is possible to
control amounts of water and solvents of the inks for forming ink
images on the intermediate transfer body, and control its viscosity
in accordance with an ink infiltration characteristic when the ink
images formed are transferred from the intermediate transfer body
to recording media. Thus, flexibility of usable recording media is
increased. Further, use of an intermediate transfer body in ink-jet
recording separates the print head having the nozzles for ejecting
inks from the recording media. Therefore, there are various
advantages such as preventing clogging of the print head through
deposition of paper powder from recording media on the nozzles.
In order to obtain higher quality images by means of ink-jet
recording systems utilizing an intermediate transfer body, however,
it is desirable to satisfy the conditions described in the
following [1] through [4].
[1] The ink images on the intermediate transfer body are formed as
images without beading and bleeding.
[2] The ink images formed on the intermediate transfer body is
transferred to the recording media without deterioration of the
images.
[3] The transferred ink images are free from offset when dried,
fixed and piled, and have abrasion resistance.
[4] The intermediate transfer body is easily cleanable after
transfer, and able to repeat forming images.
However, the following problems have arisen about the
above-mentioned item. Concerning [1], since the intermediate
transfer body used is not a recording medium that allow
infiltration of ink solvents, beading by which the neighboring ink
dots ejected onto the intermediate transfer body stick with one
another to unduly diffuse or flow, and positions or shapes of the
dots are significantly changed occurs damaging the images. Then,
transferred images naturally become damaged so that eventually high
quality images cannot be formed on the recording media.
Concerning [2], when the ink images formed on the intermediate
transfer body are transferred to the recording media, local failure
in transfer of portions of the ink images or generating state in
which ink images dissociate inside and the dissociated ink images
are transferred the intermediate transfer body and the recording
media respectively causes irregulars coloration or optical
concentration of the images on the recording media, and good images
cannot be formed.
Concerning [3], when the amount of resin is too small in the ratio
between colorant and resin that are solid components of ink images
transferred to recording media such as printing paper, or when a
nonvolatile solvent component other than water, such as organic
solvent, remains in ink images even if there is enough amount of
resin, cohesive force of the solid components of the inks that form
ink images becomes weak. This causes offset ink smear when
recording media are piled, or ink smear through abrasion.
Concerning [4], when a large amount of inks forming ink images on
the intermediate transfer body remains on the intermediate transfer
body after transfer, it gives a tremendous load on cleaning. This
not only results in problems such as reduction of recording speed
and energy consumption due to cleaning, but also causes problems
such as generation of a large amount of waste inks and that
apparatuses become larger.
In order to solve the problems, Japanese Patent Application
Laid-open No. 5-200999(1993) discloses an apparatus which emits ink
dots from an ink-jet print head onto an intermediate transfer body,
concentrates the ink by making the intermediate transfer body
absorb the solvent in the inks, and transfers the inks to a
recording media. The apparatus is one of the useful means that
enable formation of good images.
The apparatus disclosed by the Japanese Patent Application
Laid-open No. 5-200999(1993), however, has a unique problem that
efficiency of transfer to recording media is reduced due to
clogging of solvent absorption holes of the intermediate transfer
body. It makes the cleaning of residual inks on the intermediate
transfer body a big deal. Moreover, there is also a problem of much
energy consumption in recovering initial condition of the transfer
body by removing the solvent absorbed in the intermediate transfer
body by air suction and discharging absorbed water by heating.
Japanese Patent Application Laid-open No. 11-188858(1999) proposes
a method and an apparatus that first form powder soluble to or
swellable with inks on an intermediate transfer body, form images
by emitting ink drops from an ink-jet print head onto the transfer
body, and then transfer the images from the intermediate transfer
body to recording media.
The method disclosed by the Japanese Patent Application Laid-open
No. 11-188858(1999), however, consumes much energy in removal of
water taken in by the powder that is capable of absorption of
water. When images still containing water are transferred to
recording media, the water absorbed by the recording media expands
the images, damages sharpness of the images, and reduces optical
concentration, causing deterioration of the images. In imageless
portions of the intermediate transfer body where no image is
formed, there remains uncolored water absorbing resin powder. It
may cause stain on the recording media during transfer and further
deterioration of the quality of images. The image forming method
utilizing the above-mentioned process is useful as a method for
fixing images on an intermediate transfer body. In the image
forming method, however, in order to stably supply the transfer
body with powder again after transfer, a process of recoating
powder is required after cleaning of the powder in imageless
portions on the transfer body. The apparatuses for cleaning the
intermediate transfer body and powder coating take much space.
Japanese Patent Application Laid-open No. 1-146750(1989), on the
other hand, discloses an apparatus that forms a thin film of
glycerin capable of releasing oil-based inks on an intermediate
transfer body, whereon ink images are formed with oil-based inks.
Thus, use of oil-based inks as inks for forming images on recording
media enables formation of good ink images on the intermediate
transfer body.
The apparatus disclosed by the Japanese Patent Application
Laid-open No. 1-146750(1989) can provide images with high quality
and good water resistance when oil-based inks are used as described
above. The oil-based inks described above, however, may adversely
influence human bodies and environment, since they contain organic
solvents that are harmful to human bodies and environment. When the
method is carried out using water-based ink compositions taking
influence on human bodies and environment into consideration,
beading and bleeding occur due to good affinity of the water-based
inks with the glycerin film formed on the intermediate transfer
body, and images formed are distorted. There is another problem
that rapid fixing is impossible due to slow drying.
Further, Japanese Patent Application Laid-open Nos. 7-089067(1995)
and 7-256873(1995) disclose methods for carrying out ink-jet
recording by coating surfactants in advance on an intermediate
transfer body with releasing property to provide it with increased
wettability for water-based inks. These methods solve the problem
of exudation of inks on recording media by forming images with
water-based inks on an intermediate transfer body which is coated
with a surfactant in advance, and transferring them to recording
media when appropriate viscosity is attained.
The methods for solving problems in ink-jet recording using an
intermediate transfer body disclosed by the Japanese Patent
Application Laid-open Nos. 7-089067(1995) and 7-256873(1995) are
useful when images are formed on an intermediate transfer body or
recording media using an ink of a single color, such as a black ink
of same concentration, alone. They are not decisive solutions,
however, in case colored high quality images are formed by ejecting
inks with different concentrations and colors from plurality of
different nozzles onto predetermined image address points on
recording media.
It is clear as described above that there still remain problems to
be improved, although various methods have been proposed for
carrying out formation of good images on regular paper and
non-absorbing recording media, when image formation is carried out
by means of an ink-jet recording system utilizing an intermediate
transfer body. In particular, a demand for rear face printing of a
printed sheet immediately after rapid record output, or a demand
for implementation of book binding, namely cutting and folding, of
recording media immediately after output have been raised.
Therefore, further improvement is required in rapid drying and
fixing of ink images transferred from an intermediate transfer body
to recording media, and in complete fixing with good abrasion
resistance.
In order to solve such problems, methods of increasing materials
for reducing flowability of color inks (also called "image fixing
components" in this specification) and the amount of such additives
as high molecular weight resins in inks can be considered.
Excessive addition of additives to inks, however, has been possible
to cause deterioration of stability of ink discharge from an
ink-jet print head, and reduction of stability of means of coating
due to retention of resin in the means of coating due to drying of
image fixing components.
SUMMARY OF THE INVENTION
The purpose of the present invention is to provide a method and an
apparatus for ink-jet recording wherein ink images with high
quality and good abrasion resistance (fixability) without beading
and bleeding are formed on recording media in ink-jet recording
utilizing an intermediate transfer body.
In the first aspect of the present invention, there is provided an
ink-jet recording method comprising the steps of:
applying a first material that reduces flowability of ink having
colorants, to an intermediate transfer body;
forming ink image on the intermediate transfer body by applying the
ink from print head to the intermediate transfer body to which the
first material has been applied;
transferring the ink images formed on the intermediate transfer
body to a recording media; and
applying a second material to improve abrasion resistance of images
on the recording media to the intermediate transfer body before the
transfer step.
In the second aspect of the present invention, there is provided an
ink-jet recording method comprising the steps of:
applying a first material for making colorants of ink coagulate, to
an intermediate transfer body;
forming ink image on the intermediate transfer body by applying the
ink from print head to the intermediate transfer body to which the
first material has been applied;
transferring the ink images formed on the intermediate transfer
body to a recording media; and
applying a second material having resin to the intermediate
transfer body before the transfer step.
In the third aspect of the present invention, there is provided an
ink-jet recording apparatus comprising:
a first application means for applying a first material that
reduces reducing flowability of ink having colorants, to an
intermediate transfer body;
a formation means for forming ink image on the intermediate
transfer body by applying the ink from print head to the
intermediate transfer body to which the first material has been
applied;
a transfer means for transferring the ink images formed on the
intermediate transfer body to a recording media; and
a second application means for applying a second material to
improve abrasion resistance of images on the recording media to the
intermediate transfer body before the ink image is transferred by
the transfer means.
In the fourth aspect of the present invention, there is provided an
ink-jet recording apparatus comprising:
a first application portion that applies a first material for
rendering colorants of ink coagulate, to an intermediate transfer
body;
a formation portion that forms ink image on the intermediate
transfer body by applying the ink from print head to the
intermediate transfer body to which the first material has been
applied;
a transfer portion that transfers the ink image formed on the
intermediate transfer body to a recording media; and
a second application portion that applies a second material having
resin to the intermediate transfer body before the ink image is
transferred by the transfer portion.
The image fixing component to be described below is preferably used
as the above-mentioned "first material", and the supplementary
liquid to be described below is preferably used as the
above-mentioned "second material".
Further, not only paper used with ordinary recording apparatuses
but also widely cloths, plastic films, etc. capable of accepting
inks is the "recording media" of the present invention.
According to an embodiment of the present invention, the
intermediate transfer body is applied, besides coloring inks, a
first material (an image fixing component) for reducing flowability
of the coloring inks and a second material (a supplementary liquid)
for improving abrasion resistance of images on recording media
after transfer. Thus, ink images free from beading or bleeding can
be formed on the intermediate transfer body, and by transferring
the ink images to recording media, high quality images can be
formed on the recording media. Moreover, since ink images
containing the above-mentioned second material are transferred on
the intermediate transfer body, the images after transfer on the
recording media have good abrasion resistance (fixability).
The above and other objects, effects, features and advantages of
the present invention will become more apparent from the following
description of embodiments thereof taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic sectional view showing a conformation of the
image forming portion of an ink-jet recording apparatus in
accordance with an embodiment of the present invention;
FIG. 2 is a schematic sectional view showing a conformation of the
image forming portion of an ink-jet recording apparatus in
accordance with an embodiment of the present invention;
FIG. 3 is a schematic sectional view showing a conformation of the
image forming portion of an ink-jet recording apparatus in
accordance with an embodiment of the present invention;
FIG. 4 is a schematic block diagram showing conformation of a
controlling portion in accordance with an embodiment of the present
invention; and
FIG. 5 is a schematic sectional view showing a conformation of the
image forming portion of an ink-jet recording apparatus in
accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The embodiments of the present invention will be precisely
described below with reference to drawings.
First Embodiment
This embodiment applies a supplementary liquid to ink images formed
on a transfer drum 1, after the transfer drum 1, i.e. an
intermediate transfer body, is applied the inks of each color at an
ink applying portion 3, by arranging a supplementary liquid
applying portion 4 at down flow side of the ink applying portion
3.
FIG. 1 is a schematic sectional view showing a construction of the
image forming portion of an ink-jet recording apparatus in
accordance with an embodiment of the present invention.
In FIG. 1, the transfer drum 1 is an intermediate transfer body
having a releasing surface layer. The transfer drum 1 is supported
by an unshown shaft and can be rotatingly driven in the direction
of the arrow A with an unshown drum driving device. Towards
circumference of the transfer drum 1, an image fixing component
coating portion 2, an ink applying portion 3, a supplementary
liquid applying portion 4, an ink image treatment portion 5, a
transfer portion 6, a recording media separation portion 7, and a
cleaning portion 8 are arranged in this order from up flow side to
down flow side. Further, a paper feed/transportation portion 10 for
delivering a recording medium 9 from an unshown recording media
storage portion (paper feed cassette) to a nip portion to be
described below, and a paper discharge/transportation/fixing
portion 11 for discharging recording media to a paper discharge
tray 9, and having a fixing mechanism for fixing ink images on the
recording media 9 after the ink images are transferred from the
transfer body, i.e. transfer drum 1, to the recording media 9 are
arranged. Also, the ink-jet recording apparatus has an unshown
control portion.
The constructions of each above-mentioned portion are further
precisely described.
FIG. 4 is a schematic block diagram showing configuration of a
controlling portion in accordance with an embodiment of the present
invention. In an ink-jet recording apparatus wholly indicated by
reference numeral 100 in FIG. 4, CPU 101 implements control and
data processing of operation of the present ink-jet recording
apparatus. A memory 102 has a ROM (unshown) storing programs for
those procedures, etc., and a RAM (unshown) used as a work area,
etc., for implementation of those procedures. An I/F 103 is an
interface for transfer of information such as data and commands
between an ink-jet recording apparatus and an image supply
apparatus 110 that is a source of supply of image data such as host
computers.
Besides the above-mentioned portions, a transfer drum 1, an image
fixing component coating portion 2, an ink applying portion 3, a
supplementary liquid applying portion 4, an ink image treatment
portion 5, a transfer portion 6, a recording media separation
portion 7, a cleaning portion 8, a paper feed/transportation
portion 10, a paper discharge/transportation/fixing portion 11, and
a heater 14 are connected to a bus line 120. Therefore, a CPU 101
can exchange information with each portion through the pass line
120. Further, each portion, i.e. subject of control, is provided
with a sensor for detecting state. Each of detection signals
detected each portion can be transferred to the CPU 101 through the
bus line 120.
As shown in FIG. 1, a transfer drum 1, that is an intermediate
transfer body having a releasing surface layer, has two silicone
rubber layers laminated as surface layers 13a and 13b around an
aluminum support 12. The material used as the support 12 is not
particularly limited to aluminum, but metals such as nickel and
phosphate iron, thermosetting resins with excellent strength such
as acetal, or materials molded with ceramics can also be used.
Although the releasing layer in FIG. 1 has two silicone rubber
layers, the layer structure does not need to be limited to this,
but may be changed in accordance with its elastic property.
In the present embodiment, the surface of the transfer drum 1 has
releasing property so that the surface of the transfer drum 1 can
be easily cleaned leaving no ink after the transfer process.
The outermost surface layer 13a of the transfer drum 1 having a
releasing surface layer has a property of easily releasing ink
images (releasing property) on the surface. Silicone rubber is one
of the most appropriate materials for forming the surface layer
13a, since it has low surface energy and highly releasing property.
As other examples of materials for forming the surface layer 13a,
for example, fluoro-silicone rubber, phenylsilicone rubber,
fluorocarbon rubber, chloroprene rubber, nitrile rubber,
ethylene-propylene rubber, natural rubber, styrene rubber, isoprene
rubber, butadiene rubber, ethylene-propylene-butadiene copolymer,
and nitrile-butadiene rubber can be named. As especially preferable
materials, silicone rubber, fluoro-silicone rubber, phenylsilicone
rubber, fluorocarbon rubber, and chloroprene rubber can be named.
The surface layer 13b, which is an under-layer of the surface layer
13a for optimizing the elastic property of the rubber layer
constructing the surface of the support 12, can be formed by
appropriately using the materials named above.
Although the surface of the surface layer 13a is described above as
having releasing property, it is not limited to have releasing
property. From the view point of improvement of transfer ratio,
however, it is preferably a releasing material, and also a
non-permeable (non-absorbable) material. Here, releasing property
indicates characteristic of easy releasing reacting liquids (image
fixing components), inks applied on the surface, and ink images
formed by inks and reacting liquids (image fixing components), or
the like. Higher releasing property provides more advantage in
terms of transfer ratio of the ink images and load for driving
cleaning components in cleaning or the intermediate transfer body.
On the other hand, it reduces critical surface tension of the
material rendering it repelling so that liquids such as inks become
difficultly adherable to the surface and reacting liquids (image
fixing components) and ink images become difficult to be held. In
the present invention, a releasing surface indicates a surface with
critical surface tension of 30 mN/m or below, or contact angle to
water of 75.degree. or above.
Inside the transfer drum 1 is embedded a heater 14 for ensuring
temperature stability of the transfer drum 1. For the heater 14,
ordinarily used means of heating such as a halogen lamp can be
appropriately used. The preset temperature is preferably
20-100.degree. C., and more preferably 25-80.degree. C., as the
surface temperature of the transfer drum 1.
The image fixing component coating portion 2 in FIG. 1 comprises a
coating liquid container 15, an image fixing component 16, and
coating rollers 17a and 17b.
The image fixing component coating portion 2 coats the transfer
drum 1 with the image fixing component 16 in the coating liquid
container 15.
The image fixing component coating portion 2 is positioned at the
up-flow side of an ink applying portion 3 to be described below on
the transfer drum 1. The coating roller 17b is either rotated
driven by the transfer drum 1 (driven rotation), or controllably
rotated with an independent coating roller driving means (unshown).
The coating roller 17a is either rotated driven by the coating
roller 17b, or controllably rotated with an independent coating
roller driving means. Thus, the image fixing component 16 is coated
on the surface of the transfer drum 1 by rotation of the two
coating rollers 17a and 17b. The thickness of coating of the image
fixing component 16 is preferably set in the range of 0.1-10 .mu.m
depending on the concentration of the image fixing component 16.
Too low thickness of the coated image fixing component may cause
uneven reaction of the image fixing component with inks due to
irregularity of coating. Too high thickness, on the other hand, may
cause beading due to movement of coagulated inks on the image
fixing component surface. Although the coating rollers 17a and 17b
are preferably made of materials with good wettability with the
image fixing component 16, porous or concavo-convex materials such
as materials like gravure rolls can also be used.
Further, the means of applying of the image fixing component 16 is
not limited to rollers, but means capable of applying the image
fixing component 16 onto the transfer drum 1 such as a method of
controlling the amount of applying with a blade, and a method of
applying using a spray or a ink-jet print head can be used
appropriately. In particular, in the case of the ink-jet system, it
is possible to accurately apply the image fixing components to
patterns formed according to recording images. Further, the image
fixing component coating portion 2 is configured so as to enable
control disjunction from the transfer drum 1 with a junction
control apparatus (unshown).
Here, the image fixing component 16 related to the present
invention will be described in detail. An image fixing component is
a material for reducing flowability of coloring inks. In detail, it
is a liquid whose task is to reduce flowability of inks on the
intermediate transfer body by contacting with the inks to hold the
inks landed on the intermediate transfer body at the positions of
landing as far as possible. Here, image fixing includes not only
the case where colorants and resins that are parts of compositions
constructing ink react chemically or are absorbed physically
resulting in reduction of flowability of the whole ink, but also
the case where coagulation of solid components constructing ink
reduces flowability locally. Without reduction of flowability of
ink landed on the intermediate transfer body with releasing
property, the ink flows on the intermediate transfer body causing
beading and bleeding. Therefore, an image fixing component is used
to react with the ink for reducing the flowability of the ink
brought in touch with it and make the ink landed on the
intermediate transfer body with releasing property to be held at
the position of landing. Thus, beading and bleeding can be
restrained to occur even when ink drops are brought in touch with
one another on the intermediate transfer body.
As an image fixing component, materials that coagulate ink when
brought in touch with the ink, such as liquids containing metal
salts, are suitable. As the most suitable metal salts comprising an
image fixing component 16, multivalent metal salts can be named.
Multivalent metal salts consist of multivalent metal ions with two
or more valences and anions bonded to the multivalent metal ions.
As concrete examples of multivalent metal ions, bivalent metal ions
such as Ca.sup.2+, Cu.sup.2+, Ni.sup.2+, Mg.sup.2+, and Zn.sup.2+,
and trivalent metal ions such as Fe.sup.3+ and Al.sup.3+ can be
named. As anions bonded to them, anions such as Cl.sup.-,
NO.sub.3.sup.-, SO.sub.4.sup.2-, I.sup.-, Br.sup.-,
ClO.sub.3.sup.-, RCOO.sup.- (R is an alkyl group) can be named.
The image fixing component 16 may contain water-soluble organic
solvents named below together with metal salts such as the
multivalent metal salts described above. As the water-soluble
organic solvents, for example, amides such as dimethylformamide and
dimethylacetamide, ketones such as acetone, ethers such as
tetrahydrofuran and dioxane, polyalkylene glycols such as
polyethylene glycol and polypropylene glycol, alkylene glycols such
as ethylene glycol, propylene glycol, butylenes glycol, triethylene
glycol, 1,2,6-hexanetriol, thidiglycol, hexylene glycol and
diethylene glycol, lower alkyl ethers of multivalent alcohols such
as ethylene glycol methyl ether, diethylene glycol monomethyl ether
and triethylene glycol monomethyl ether, monovalent alcohols such
as ethanol, isopropyl alcohol, n-butyl alcohol and isobutyl
alcohol, glycerin, N-methyl-2-pyrilidone,
1,3-dimethyl-2-imidazolidinone, triethanolamine, sulfolane and
dimethyl sulfoxide can be named. The content of water-soluble
organic solvents such as those named above in the image fixing
component 16 is in the range of 5 to 60% by weight, and preferably
in the range of 5 to 40% by weight, of the total weight of the
image fixing component, although there is no particular limit.
Further, the image fixing component 16 may contain a coagulation
supplement such as water-soluble resins, water-soluble
cross-linking agents and acid solutions. Preferably usable
materials may be those that can coexist with multivalent metal
salts. As a water-soluble resin, polyvinyl alcohol and polyvinyl
pyrrolidone and the like can be used. Since these coagulation
supplements have relatively high molecular weight, they can
strengthen internal cohesive force of ink coagulation images formed
by their simultaneous use with multivalent metal salts. As a
result, transfer ratio of the ink coagulation images and their
abrasion resistance can be strengthened.
Further, the image fixing component 16 may contain a coating aid
for the purpose of ensuring even coating of the image fixing
component 16 on the transfer drum 1. A surfactant may be preferably
used as the coating aid. As the surfactant, for example, Surflon
S-141 (trade name, from Seimi Chemical Co.), Silwet L-77 (trade
name, from Nippon Unicar Co.) and the like can be used. The
surfactant used in the present invention is not limited to them,
but various other surfactants such as fluorine-based surfactants,
silicone-based surfactants, water-soluble cationic surfactants,
nonionic surfactants, and ampholytic surfactants can be used.
Preferable concrete examples of cationic surfactants are aliphatic
amine salts, quaternary ammonium salts, sulfonium salts,
phosphonium salts, and the like.
Preferable concrete examples of nonionic surfactants are
fluorine-based ones, silicone-based ones, acrylic acid copolymers,
polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers,
polyoxyethylene secondary alkyl ethers, polyoxyethylene sterol
ethers, polyoxyethylene lanolin derivatives, ethylene oxide
derivatives of alkylphenol formalin condensates,
polyoxyethylene-polyoxypropylene block copolymers, fatty acid ester
types of polyoxyethylene-polyoxypropylene alkyl ether
polyoxyethylene compounds, polyethylene oxide condensate type
polyethylene glycol fatty acid esters, fatty acid monoglycerides,
polyglycerine fatty acid esters, sorbitan fatty acid esters,
propyleneglycol fatty acid esters, sucrose fatty acid esters, fatty
acid alkanolamides, polyoxyethylene fatty acid amides,
polyoxyethylene alkylamine oxides, and the like.
Preferable concrete examples of ampholytic surfactants are
carboxybetaine types, aminocarboxylic acid salts, lecithin, and the
like.
The amount of addition of these surfactants is preferably about
0.05-10% by weight, more preferably 0.1-5% by weight, of the image
fixing component 16.
Additives such as viscosity modifiers, pH adjusters, antiseptics,
and antioxidants may be added to the image fixing component 16, if
necessary. Although the image fixing component 16 of the present
invention is preferably colorless, they may be light-colored so
long as it does not change the color tone of colored inks when
mixed with them on recording media. Further, physical properties of
the image fixing component 16 including above-mentioned formation
materials are preferably adjusted so that its viscosity at about
25.degree. C. is in the range of 1-30 cps. (mPas).
The image fixing component 16 in this embodiment is configured
including metal salts, while it may be configured without metal
salts as long as it reduces flowability of inks.
In FIG. 1, the ink applying portion 3 forms ink images by applying
inks at least containing colorants from the print head to an
intermediate transfer body coated with an image fixing component
such as mentioned above, in accordance with image signals sent from
the control portion.
In FIG. 1, the ink applying portion 3 is positioned at down flow
side of the image fixing component coating portion 2 on the
transfer body, and comprising print heads 18a, 18b, 18c, and 18d.
In the present embodiment, the print heads 18a, 18b, 18c, and 18d
are comprehensively called a print head 18. In an ink-jet recording
apparatus related to the present embodiment, a line type ink-jet
print head of the type that uses a heater element (a thermoelectric
conversion element) is used as the print head 18. The print heads
18a, 18b, 18c, and 18d are arranged at constant intervals in the
direction of the circumference of the transfer drum 1. Although
line type ink-jet print heads are used in the construction of FIG.
1, a print head with a row of plurality of nozzles for inks of
different colors aligned in a predetermined range in the direction
of circumference or the direction of the shaft (direction
perpendicular to the paper in FIG. 1) of the transfer drum 1 (to be
called a "serial type print head" below, in this specification) may
be used to form images sequentially on the transfer drum 1 by
scanning this print head in the direction of the shaft. In the case
of a serial head, rotary driving of the transfer drum 1 is stepwise
driving against the row of nozzles of the head. Further, the
ink-jet print head is not limited to the type that uses an
above-mentioned heater element, but any type that can eject inks
from nozzles such as one driven by a piezoelectric element can be
used.
The four print head 18 described above is so conformed that each
applies ink of different color. In the conformation of FIG. 1, the
print head 18a applies yellow (Y), 18b applies magenta (M), 18c
applies cyan C, and 18d applies black (K). The print head 18
consisting of them is supplied with inks of different colors from
(unshown) ink tanks. The heating element of each print head
generates heat in accordance with image signals corresponding to
each color received from the control portion, and raises the
temperature of ink supplied from each ink tank to generate bubbles.
Expansion of the generated bubbles eject ink drops from plurality
of nozzles of each print head 18. The number of ink-jet print heads
conforming the ink applying portion, the order of ink colors
ejected to the transfer drum 1, and the hue of inks used in the
present invention are not limited by the description above.
The ink images formed on the transfer drum 1 should be mirror
images of the images to be formed finally on recording the medium
9, considering that they are reversed on transfer. The image
signals supplied to the print head 18 should naturally be image
signals corresponding to the mirror images. Therefore, the control
portion implements a mirror revere treatment (treatment for
obtaining reverse data) to image signals sent from an image supply
apparatus 110 (i.e. image signals corresponding to the images to be
formed finally on the recording medium 9). Thus, the image signals
corresponding to the mirror images are obtained and supplied to the
print head.
The inks used in the ink applying portion 3 are not particularly
limited, but any of generally used ink-jet inks can be used.
Especially, pigment inks can be suitably used in the present
embodiment, since they are not easily permeable to recording media
and excellent in water resistance and light resistance in
comparison with dye inks. Water-based pigment inks suitably usable
in the present embodiment will be described below.
Pigments in pigment inks are used in the range of 1-20% by weight,
preferably 2-12% by weight, of the total weight of the pigment
inks. As the pigments used in the present embodiment are those
named concretely below.
As a black pigment, carbon black can be named. For example, carbon
black produced by the furnace method or the channel method having
characteristics such as primary particle diameter of 15-40 m.mu.
(nm), specific surface area by BET method of 50-300 m.sup.2/g, DBP
absorption value of 40-150 ml/100 g, volatile portion of 0.5-10%,
and pH value of 2-9. Commercial products with such characteristics
are, for example, No. 2300, No. 900, MCF88, No. 33, No. 40, No.45,
No. 52, MA7, MA8, No. 2200B (from Mitsubishi Chemical), RAVEN1255
(from Columbia), REGAL400R, REGAL330R, REGAL660R, MOGUL L (from
Cabot), Color Black FW1, COLOR Black FW1, COLOR Black FW18, Color
Black S170, Color Black S150, Printex 35, Printex U (from Degussa),
etc., can be used preferably.
As a yellow pigment, for example, C. I. Pigment Yellow 1, C. I.
Pigment Yellow 2, C. I. Pigment Yellow 3, C. I. Pigment Yellow 13,
C. I. Pigment Yellow 16, C. I. Pigment Yellow 83 can be named. As a
magenta pigment, for example, C. I. Pigment Red 5, C. I. Pigment
Red 7, C. I. Pigment Red 12, C. I. Pigment Red 48 (Ca), C. I.
Pigment Red 48 (Mn), C. I. Pigment Red 57 (Ca), C. I. Pigment Red
112, C. I. Pigment Red 122 can be named. As a cyan pigment, for
example, C. I. Pigment Blue 1, C. I. Pigment Blue 2, C. I. Pigment
Blue 3, C. I. Pigment Blue 15:3, C. I. Pigment Blue 16, C. I.
Pigment Blue 22, C. I. Pigment Blue 4, C. I. Pigment Blue 6 can be
named. Needless to say, the present embodiment is not limited by
them. Besides those named above, any of self-dispersed pigments,
resin-dispersed pigments, and microencapsulated pigments can be
used.
As a dispersing agent for dispersing above-mentioned pigments in
water-based media used for production of water-based pigment inks,
any water-soluble resins can be used. Among them, those with weight
average molecular weight in the range of 1,000-30,000 can be
preferably used, and those with weight average in the range of
3,000-15,000 can be more preferably used. As concrete examples of
such dispersing agents, block copolymers, random copolymers, graft
copolymers or their salts comprising two or more monomers (of which
at least one is a hydrophilic polymerizable monomer) selected from
styrene, styrene derivatives, vinyl naphthalene, vinyl naphthalene
derivatives, aliphatic alcohol esters of .alpha.,.beta.-ethylenic
unsaturated carboxylic acids, acrylic acid, acrylic acid
derivatives, maleic acid, maleic acid derivatives, itaconic acid,
itaconic acid derivatives, fumaric acid, fumaric acid derivatives,
vinyl acetate, vinylpyrrolidone, acrylamide, and their derivatives
can be named. Natural resins such as rosin, shellac, and starch can
also be used preferably. These resins are soluble in aqueous
solutions in which a base is dissolved, i.e. they are
alkali-soluble resins. The water-soluble resins used as pigment
dispersing agents are preferably contained in the range of 0.1-5%
by weight of total weight of pigment inks.
Especially, in the case of pigment inks containing above-mentioned
pigments, the whole pigment inks are preferably adjusted neutral or
alkaline. Thus, solubility of the water-soluble resins used as
pigment dispersing agents is improved, resulting in pigment inks
more excellent in long-life nature. In this case, however, it is
preferable to adjust pH in a range of 7-10, since the solutions may
cause corrosion of various parts used in ink-jet recording
apparatuses. As the pH adjusting agents used here, for example,
various organic amines such as diethanolamine and triethanolamine,
inorganic alkalis such as alkali metal hydroxides, e.g. sodium
hydroxide, lithium hydroxide, and potassium hydroxide, organic
acids and mineral acids. Pigment inks are conformed by dispersing
or dissolving in water-based media colorants such as pigments and
water-soluble resins as dispersing agents described above.
Water-based solvents suitable for pigment inks are mixed solvents
of water and water-soluble organic solvents, and it is preferable
to use ion-exchanged water (deionized water) as the water instead
of ordinary water containing various ions.
As examples of the water-soluble organic solvent used as a mixture
with water, alkyl alcohols with 1-4 carbon atoms such as methyl
alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol,
n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, amides such
as dimethylformamide and dimethylacetamide, ketones or ketoalcohols
such as acetone and diacetone alcohol, ethers such as
tetrahydrofuran and dioxane, polyalkylene glycols such as
polyethylene glycol and polypropylene glycol, alkylene glycols
having alkylene groups with 2-6 carbon atoms such as ethylene
glycol, propylene glycol, butylene glycol, triethylene glycol,
1,2,6-hexane triol, thioglycol, hexylene glycol and diethylene
glycol, glycerine, lower alkyl ethers of multivalent alcohols such
as ethylene glycolmonomethyl (or ethyl) ether, diethylene glycol
methyl (or ethyl) ether and triethylene glycol methyl (or ethyl)
ether, N-methyl-2-pyrrolidone, 2-pyrrolidone, and
1,3-dimethyl-2-imidazolidinone can be named. Among these many
water-soluble organic solvents, multivalent alcohols such as
diethylene glycol and lower alkyl ethers of multivalent alcohols
such as triethylene glycol methyl (or ethyl) ether are
preferable.
Content of the above-mentioned water-soluble organic solvents in
pigment inks is generally in a range of 3-50% by weight of total
weight of the pigment inks, and more preferably in a range of 3-40%
by weight. Content of water used is in a range of 10-90% by weight
of total weight of the pigment inks, and preferably in a range of
30-80% by weight.
Besides the above-mentioned ingredients, if necessary, surfactants,
antifoaming agents, and preservatives may be added arbitrarily to
obtain pigment inks with desired physical properties. Especially,
surfactants that function as permeation promoters need to be added
in appropriate amounts to play the role of helping the liquid
ingredients of the image fixing components and pigment inks
permeate recording media rapidly. The amount of addition is
0.05-10% by weight, and preferably 0.5-5% by weight. As an anionic
surfactant, any of those generally used such as carboxylic acid
salts, sulfate esters, sulfonic acid salts, and phosphoric acid
salts can be suitably used.
In order to prepare a pigment ink comprising above-mentioned
materials, the pigment is first added to an aqueous medium at least
containing a water-soluble resin as a dispersing agent and water.
Then, after mixing and agitation, dispersion is implemented using a
dispersing means to be described below, and centrifugal separation
is carried out if necessary to obtain a desired dispersion. Then,
after addition of a sizing agent and additives appropriately
selected as described above, a pigment ink is obtained by
agitation.
In case an alkali-soluble resin described above is used as the
dispersing agent, addition of base is required to dissolve the
resin. As the base used here, organic bases such as
monoethanolamine, diethanolamine, triethanolamine,
aminomethylpropanol and ammonia and inorganic bases such as
potassium hydroxide and sodium hydroxide are preferably used.
In preparation of a pigment ink, it is effective to implement
premixing for 30 minutes by agitation of aqueous medium containing
the pigment before dispersing treatment Such a premixing treatment
is preferable because the treatment can improve wettability of the
pigment surface and promote adsorption of the dispersing agent on
the pigment surface.
The dispersing machine used in dispersing treatment of the
above-mentioned pigments can be any of the generally used
dispersers such as ball mills, roll mills, and sand mills. Among
them high speed type sand mills are preferably used. As such, for
example, super mills, sand grinders, beads mills, agitator mills,
grain mills, dinoh mills, par mills, Cobol mills (all are trade
names) can be named.
In an ink-jet recording method using pigment inks, pigments with
optimum particle size distribution are used because of request of
clogging resistance, etc. As a method for obtaining pigments with
desirable particle size distribution, minimization of the size of
grinding media of the disperser, maximization of filling rate of
grinding media, lengthening of the time of treatment, delaying of
rate of eject, classification with a filter or a centrifuge after
grinding, and combination of them can be named.
In the ink applying portion 3, pigment inks such as described above
are used to apply ink drops to an intermediate transfer body
(transfer drum 1) coated with the above-mentioned image fixing
component 16 by means of a print head having plurality of nozzles
capable of controllably ejecting in accordance with image signals
sent from the control portion, to form ink images on the transfer
drum 1 (an ink image forming step). In the present embodiment, the
inks rapidly coagulate through reaction of the image fixing
component 16 coated on the transfer drum 1 and the pigment inks
applied from the print head 18, resulting in formation of ink
coagulation images on the transfer drum 1. Especially in the
present embodiment, for example, metal salts, i.e. metal ions that
function as image fixing components rapidly react with pigment inks
and coagulate them. Thus, good ink coagulation images without
beading or bleeding can be formed on the transfer drum 1. Although
pigment inks using pigments as colorants have been described above
as an example, the present embodiment is not limited with them but
mixed inks containing dyes added to pigments, for example, can also
be used. Further, water-soluble resins and cross-linking agents can
also be added to the inks and/or image fixing components to
strengthen internal coagulation force of the ink coagulation
images, as long as the image fixing components contain metal salts.
The ink applying portion 3 of FIG. 1 is there to realize the ink
image formation process described above.
Next, in FIG. 1, the supplementary liquid applying portion 4
comprises a print head 19 for applying supplementary liquid. In the
supplementary liquid applying portion 4, supplementary liquid 21 is
applied from the print head 19 for applying supplementary liquid in
accordance with the ink images 20 formed in the ink applying
portion 3.
In FIG. 1, a supplementary liquid applying portion 4 is arranged at
down flow side of the ink applying portion 3 on the transfer drum
1. In the present embodiment, a line-type ink-jet print head of the
type that uses heating elements is used as the print head 19 for
applying supplementary liquid. The print head 19 for applying
supplementary liquid is positioned at down flow side of the
circumference direction of the transfer drum 1 parallel with the
print heads 18a, 18b, 18c and 18d of the print head of the ink
applying portion 3. Although a line-type ink-jet print head is used
as the print head for applying supplementary liquid in FIG. 1, a
conventional serial-type print head can naturally be used to apply
the supplementary liquid sequentially to the ink images 20 formed
on the transfer drum 1 by scanning the print head in the direction
of the shaft. Further, the ink-jet print head is not limited by the
type described above, but any type such as ones driven by a
piezoelectric element can be used as long as they can eject
inks.
Further, although a print head is used as the means for applying
supplementary liquid in the present embodiment, any means capable
of applying supplementary liquid to the transfer drum, such as a
spray or a roller for applying supplementary liquid, can be
applied.
The image signals supplied to the print head 19 for applying
supplementary liquid are logical sum signals obtained by logically
summing four binary format image signals supplied to the print
heads 18a, 18b, 18c and 18d of the ink applying portion 3. Thus,
the supplementary liquid 21 is not applied where the inks are not
deposited on the transfer drum 1, but the supplementary liquid 21
is applied only where the inks are deposited.
The supplementary liquid related to the present embodiment will be
described below.
The supplementary liquid is a material for improving abrasion
resistance (fixability) of final images on recording media 9, i.e.
target of transfer. As one of the methods for improving abrasion
resistance of images on recording media, it is effective to have
the images contain much resin that contributes to adhesiveness to
recording media. Applying the supplementary liquid containing resin
to ink images 20 formed on the intermediate transfer body, i.e. the
transfer drum 1, increases the ratio of resin as a component of ink
images 20. Since the ink images are transferred in such a
condition, the images after transfer naturally contain much resin.
Thus, abrasion resistance of the images after transfer increases.
Further in applying supplementary liquid 21 to ink images 20 on the
transfer drum 1, application of the supplementary liquid 21 before
formation of ink images 20 adds to their releasing property from
the transfer drum 1. Also, application of the supplementary liquid
21 after formation of ink images adds to their adhesiveness to
recording media 9, and as a result is advantageous in transferring
property. In the present embodiment, the supplementary liquid 21
comprises, as main ingredients, ingredients other than pigments and
dyes that are colorants used in ordinary inks.
In the composition of the supplementary liquid 21, water-soluble
resins and water-soluble cross-linking agents can be used as the
resin for improving abrasion resistance. Although any water-soluble
resins can be used, it is appropriate to change kinds of the
water-soluble resins in accordance with application means. In case
means for applying supplementary liquid 21 is a print head, for
example, those with weight average molecular weight preferably in
the range of 1,000-30,000, more preferably in the range of
3,000-15,000, are used. In the case of means such as roller
coating, those with even higher weight average molecular weight can
be used. As concrete examples of such water-soluble resins, block
copolymers, random copolymers, graft copolymers or their salts
comprising two or more monomers (of which at least one is a
hydrophilic polymerizable monomer) selected from styrene, styrene
derivatives, vinyl naphthalene, vinyl naphthalene derivatives,
aliphatic alcohol esters of a,.beta.-ethylenic unsaturated
carboxylic acids, acrylic acid, acrylic acid derivatives, maleic
acid, maleic acid derivatives, itaconic acid, itaconic acid
derivatives, fumaric acid, fumaric acid derivatives, vinyl acetate,
vinyl alcohol, vinylpyrrolidone, acrylamide, and their derivatives
can be named. Alternatively, natural resins such as rosin, shellac,
and starch can be used preferably. These resins are alkali-soluble
resins that are soluble in aqueous solutions in which bases are
dissolved. These water-soluble resins are preferably contained in
the range of 0.1-20%, more preferably 0.1-10%, by weight of the
total weight of the supplementary liquid 21.
Use of water-soluble resins as the supplementary liquid 21 as
described above results in existence of many resin layers on the
images after transfer as described below. Thus, abrasion resistance
(fixability) of final images on the recording media 9 is
improved.
As the pH adjusters used for dissolution of resins, for example,
various organic amines such as diethanolamine and triethanolamine,
inorganic alkalis such as sodium hydroxide, lithium hydroxide and
potassium hydroxide, organic acids and mineral acids are named. The
water-soluble resins such as described above are dispersed or
dissolved in aqueous solvents to form the supplementary liquid
21.
Water-based solvents suitable to form the supplementary liquid 21
are mixed solvents of water and water-soluble organic solvents, and
it is preferable to use ion-exchanged water (deionized water) as
the water instead of ordinary water containing various ions.
As examples of the water-soluble organic solvent used as a mixture
with water, alkyl alcohols with 1-4 carbon atoms such as methyl
alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol,
n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, amides such
as dimethylformamide and dimethylacetamide, ketones or ketoalcohols
such as acetone and diacetone alcohol, ethers such as
tetrahydrofuran and dioxane, polyalkylene glycols such as
polyethylene glycol and polypropylene glycol, alkylene glycols
having alkylene groups with 2-6 carbon atoms such as ethylene
glycol, propylene glycol, butylene glycol, triethylene glycol,
1,2,6-hexane triol, thioglycol, hexylene glycol and diethylene
glycol, glycerine, lower alkyl ethers of multivalent alcohols such
as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol
methyl (or ethyl) ether and triethylene glycol methyl (or ethyl)
ether, N-methyl-2-pyrrolidone, 2-pyrrolidone, and
1,3-dimethyl-2-imidazolidinone can be named. Among these many
water-soluble organic solvents, multivalent alcohols such as
diethylene glycol and lower alkyl ethers of multivalent alcohols
such as triethylene glycol monomethyl (or ethyl) ether are
preferable.
Content of the above-mentioned water-soluble organic solvents in
the supplementary liquid 21 is generally in a range of 3-50% by
weight of total weight of the supplementary liquid 21, and more
preferably in a range of 3-40% by weight. Content of water used is
in a range of 10-90% by weight of total weight of the supplementary
liquid 21, and preferably in a range of 30-80% by weight.
Besides the above-mentioned ingredients, if necessary, surfactants,
antifoaming agents, and preservatives may be added arbitrarily to
obtain supplementary liquid 21 with desired physical properties.
Especially, surfactants that function as surface tension adjusters
for ensuring stable ejection of the supplementary liquid 21 from
the print head 19 for applying supplementary liquid need to be
added in appropriate amounts. The amount of addition, for example,
is 0.05-10% by weight, and preferably 0.5-5% by weight.
As anionic surfactant that can be added to the supplementary liquid
21, any of those generally used such as carboxylic acid salts,
sulfate esters, sulfonic acid salts, and phosphoric acid salts can
be preferably used. Further, the supplementary liquid 21 may
include the above-mentioned image fixing component.
Next, in FIG. 1, the ink image treatment portion 5 comprises an air
knife 22 and a solvent saucer 23.
The ink image treatment portion 5 carries out treatment of ink
image 20 to ensure more optimum condition in transfer of the ink
image 20 formed in the ink applying portion 3 to the recording
media 9.
In FIG. 1, an ink image treatment portion 5 is arranged at down
flow side of a supplementary liquid coating portion 4. The ink
image treatment portion is provided with an air knife 22 that sends
warm air heated by an unshown heater to remove the liquid media in
the ink, mainly water in the ink, by evaporation or separation, and
a solvent saucer 23. Namely, the ink image treatment portion 5 is
provided for the purpose of controlling transfer characteristics of
ink image 20 to recording media 9 with the amount of air sent from
the air knife and the amount of heat related to the temperature of
air, taking in account the permeability of the ink image 20, ink
coagulation image, to the recording media 9.
Although an air knife 22 is used as a means of drying of the ink
image 20 in the present embodiment, any means such as an infrared
heater that can control temperature and that can control
characteristics of ink images can be used.
In FIG. 1, the transfer portion 6 comprises a transfer roller 26.
The paper feed/transportation portion 10 comprises transportation
rollers 24a and 24b, and transportation guides 25a and 25b.
In the transfer portion 6, ink images 20 on the transfer drum 1 is
press-transferred with the transfer roller 26 on the recording
media 9 transported with transportation rollers 24a and 24b and
transportation guides 25a and 25b of the paper feed/transportation
portion 10.
The transfer roller 26 is positioned to pass the recording media 9
through the nip portion between the transfer drum 1 and the
transfer roller 26, and can be formed with a rubber roller or a
metal roller. In the transfer portion 6, control of release of
pressure on the transfer drum 1 is possible with an unshown
pressure control apparatus. In the figure, the transportation
rollers 24a and 24b rotate in the direction of an arrow B, and the
transfer roller 26 rotates in the direction of C. The transfer
roller 26 is either rotated driven by the transfer drum 1 (driven
rotation) through the recording media 9, or controllably rotated
with an independent transfer roller driving means (unshown). In
FIG. 1, rotation of the transfer roller is driven rotation.
Although the transfer roller 26 is conformed to pressurize the
transfer drum 1 with a linear load of 0.6 kg/cm.sup.2 through the
recording media 9 during transfer in the present embodiment, it is
not limited to this.
In FIG. 1, the recording medium separation portion 7 comprises a
paper lifter 27.
In the recording media separation portion 27, the paper lifter 27
works in accordance with transportation timing of the recoding
media 9.
After the above-mentioned transfer finishes, the paper lifter 27 is
driven by an unshown driving device to separate the recording media
9 from the transfer drum 1, and guides the recording media 9 to the
paper discharge/transportation/fixing portion 11 by means of
transportation guides 28a and 28b.
In FIG. 1, the paper discharge/transportation/fixing portion 11
comprises transportation guides 18a and 28b and
transportation/fixing rollers 29a and 29b.
In the paper discharge/transportation/fixing portion 11, the
recording media 9 on which ink images are transferred and which is
guided with transportation guides 28a and 28b are heated with
transportation/fixing rollers 29a and 29b equipped with infrared
heaters to fix the ink images, and sent to an unshown paper
discharge tray with rotation of the rollers. Recording finishes by
the above operations.
As the transportation/fixing rollers 29a and 29b, conventionally
known fixing rollers can be used, preferably at a temperature of
30-200.degree. C. The rollers are formed with such materials as
metal rollers and silicone rubber. Silicone oil, etc. may be coated
on the surface of the rollers to improve releasing property.
In FIG. 1, a cleaning portion 8 comprises a cleaning liquid 30, a
cleaning liquid holding part 31 holding the cleaning liquid 30, a
cleaning liquid supply roller 32a for coating the transfer drum 1
with the cleaning liquid 30 to remove dust, and a cleaning roller
32b.
In the same figure, the cleaning roller 32b is either driven by the
transfer drum 1 (driven rotation) or capable of being controllably
driven with an unshown driving means. The cleaning liquid supply
roller 32a is either driven by the cleaning roller 32b or capable
of being controllably driven with an unshown driving means. As
described above, the cleaning liquid 30 is coated on the transfer
drum 1 by the rotation of the cleaning liquid supply roller 32a and
the cleaning roller 32b. The cleaning portion 8 carries out
cleaning of the transfer drum 1 as described above.
Although there is no limit in the device conformation or the
cleaning liquid 30 of the cleaning portion 8, it is preferable to
use the aqueous solution containing surfactant, water-soluble
organic solvent and so on used for the above-mentioned image fixing
component 16.
A series of operation of an ink-jet recording apparatus of the
present embodiment with the above-mentioned conformation will be
described in detail below with reference to FIG. 1.
When the power to the ink-jet recording apparatus is switched on,
the transfer drum 1 starts driven rotation, and each heater inside
the transfer drum 1, of the air knife 22, and of the
transportation/fixing rollers 29a and 29b is turned on and starts
heating each portion to each preset temperature. On receiving image
signals from an image supply device 110 such as a computer, the
coating roller 17b conforming the image fixing component coating
portion 2 abuts the transfer drum 1. Then, rotation of the coating
roller 17a allows the image fixing component 16 to coat the coating
roller 17b through the coating roller 17a, and the transfer drum 1
is evenly coated with the image fixing component 16. After the
image fixing component 16 is coated on the transfer drum 1 in one
rotation of the transfer drum 1, the coating roller 17b is detached
from the transfer drum 1. Naturally, while the image fixing
component 16 is being coated on the transfer drum 1, ink images can
be formed in the ink applying portion 3 on the region of the
transfer drum 1 where the image fixing component 16 is coated.
Here, multivalued image signals (to be called "external image
signal" below in the specification) corresponding to each ink color
(C, M, Y, K) used in the present embodiment are sent from the image
supply apparatus 110, and are converted to binary format image
signals corresponding to the multivalued image signals, Y, M, C, K.
Then, a mirror image inversion treatment is applied to the binary
format image signals corresponding to each color to obtain binary
reverse image signals corresponding to each color.
Next, the binary reverse image signals corresponding to each color
are sent to each print head 18, wherein, concurrently with rotation
of the transfer drum 1, inks of each color are sequentially ejected
from the print heads 18a, 18b, 18c and 18d and applied to the
transfer drum 1. In the occasion, the inks react with the image
fixing component 16 coated on the transfer drum 1 to form ink
images 20 with coagulated colors on the transfer drum 1. Obviously
the ink images are mirror images of the images to be formed finally
on the recording media 9.
Subsequently, logical sum signals of the binary reverse image
signals corresponding to each color are sent to the print head 19
for applying the supplementary liquid 21, and the supplementary
liquid 21 is ejected from the print head 19 for applying
supplementary liquid concurrently with rotation of the transfer
drum 1 and applied to the ink images 20, i.e. ink coagulation
images, on the transfer drum 1. The ink images 20 applied the
supplementary liquid are dried in the ink treatment portion 5 by
evaporation of the solvent for optimization of the condition for
transfer to be implemented later.
The recording media 9 are transported by means of the
transportation rollers 24a and 24b to the transfer portion 6, so
that front edge of ink images formed on the transfer drum 1 as
described above and the recording media 9, i.e. transfer receiving
media, lap in the nip portion, i.e. position of transfer. In the
transfer portion 6, the transfer roller 26 is activated when an
unshown sensor detects that the front edge of the recording media 9
reached the nip portion of the transfer drum 1 and the transfer
roller 26. Then, the transfer roller 26 is pressed against the
transfer drum 1 across the recording media 9, preset transfer
pressure is generated by means of a pressure control apparatus, and
the ink images 20 on the transfer drum 1 are transferred to the
recording media 9.
Next, at the same time when an unshown sensor detects that the
front edge of the recording medium 9 is discharged from the
transfer portion 6, the paper lifter 27 is activated, inserted
between the transfer drum 1 and the recording medium 9, and
separates the recording medium 9 from the transfer drum 1. Then,
heat and pressure are applied to the recording medium 9 separated
from the transfer drum 1 for fixing treatment by means of the
transportation guides 28a and 28b, and the transportation/fixing
rollers 29a and 29b, and the recording medium 9 is discharged to a
discharge tray. After all the inks on the transfer drum 1 are
transferred to the recording medium 9, the transfer roller 26 and
the paper lifter 27 are detached.
Next, the cleaning roller 32b is abutted to the transfer drum 1,
and cleans the surface of the transfer drum 1 by coating the
cleaning liquid 30. After one rotation of the transfer drum 1, the
cleaning roller 32b is detached from the transfer drum 1. In case
recording is continued, the above-mentioned operation is repeated
corresponding to external image signals. In case power is turned
off to finish recording operation, after each heater is turned off
and rotation of the transfer drum 1 is stopped, power to the
ink-jet recording apparatus is turned off to finish operation of
the apparatus.
As described above, in the present embodiment, the image fixing
component coating portion 2 is so conformed that an intermediate
transfer body, i.e. transfer drum 1, is coated with an image fixing
component 16 at least containing metal salts, and then inks are
applied to at least part of the coated region to form ink images in
an ink applying portion 3, wherein rapid reaction of metal ions in
the image fixing component 16 with pigment inks causes coagulation
forming ink images of the state. Thus, good ink images 20 without
beading or bleeding are formed on the intermediate transfer body.
Further, a supplementary liquid 21 containing resins for enhancing
adhesiveness to the recording medium is applied to the ink images
20, and the ink images 20 are dried in the ink treatment portion 5
and transferred to a recording medium 9 in the transfer portion 6.
Therefore, high quality images without beading or bleeding and with
good abrasion resistance (fixability) to prevent wearing of inks on
the recording media after transfer can be formed on the recording
media. Transfer efficiency may also be improved, since releasing
property and adhesiveness of ink images during transfer are
enhanced with the image fixing component 16 and the supplementary
liquid 21.
Examples of the present embodiment using example of the
above-mentioned image fixing component, colored inks, and
supplementary liquid are concretely described below.
EXAMPLE 1
In the description blow, parts (pts) and % are weight-based unless
otherwise noticed. Total amounts of both inks and image fixing
components are adjusted with water to 100 parts.
[Preparation of Pigment Inks]
First, black, cyan, magenta and yellow pigment inks each containing
pigment and anionic compounds were prepared as described below.
(Preparation of Pigment Ink K1)
<Preparation of Pigment Dispersion>
TABLE-US-00001 Styrene-acrylic acid-ethyl acrylate copolymer 1.5
parts (acid value 240, weight average molecular weight = 5,000)
Monoethanolamine 1.0 parts Diethylene glycol 5.0 parts
Ion-exchanged water rest
The above-mentioned ingredients were heated in a water bath at
70.degree. C. to dissolve the resin completely. To the solution, 10
parts of newly experimentally produced carbon black (MCF88, from
Mitsubishi Chemical) and 1 parts of isopropyl alcohol were added,
premixed for 30 minutes, and dispersion-treated under the condition
described below.
TABLE-US-00002 Dispersion machine: a sand grinder (from Igarashi
Machinery) Grinding media: zirconium beads, 1 mm diameter Filling
ratio: 50% (by volume) Grinding time: 3 hours
Further, black pigment dispersion was prepared by centrifugation
(12,000 rpm, 20 min.) to remove coarse particles.
<Preparation of Inks>
A black pigment ink K1 containing pigment was prepared using the
above-mentioned dispersion by mixing the ingredients in the
composition shown below. The surface tension of the ink was 34
mN/m.
TABLE-US-00003 Above-mentioned pigment dispersion 30.0 parts
Glycerin 10.0 parts Ethylene glycol 5.0 parts 2-pyrrolidone 5.0
parts Acethylenol EH (from Kawaken Fine Chemical) 1.0 parts
Ion-exchanged water rest
(Preparation of Pigment Ink C1)
A cyan-colored pigment ink C1 was prepared in the same manner as in
the preparation of pigment ink K1 except that 10 parts of carbon
black (MCF88, from Mitsubishi Chemical) used for preparation of
pigment ink K1 was replaced by pigment blue 15.
(Preparation of Pigment Ink M1)
A magenta-colored pigment ink M1 was prepared in the same manner as
in the preparation of pigment ink K1 except that 10 parts of carbon
black (MCF88, from Mitsubishi Chemical) used for preparation of
pigment ink K1 was replaced by pigment red 7.
(Preparation of Pigment Ink Y1)
A yellow-colored pigment ink Y1 was prepared in the same manner as
in the preparation of pigment ink K1 except that 10 parts of carbon
black (MCF88, from Mitsubishi Chemical) used for preparation of
pigment ink K1 was replaced by pigment yellow 74.
[Preparation of an Image Fixing Component]
Next, an image fixing component containing a multivalent metal salt
and a surfactant was prepared as described below.
(Preparation of Image Fixing Component R1)
A composition of the ingredients shown below was mixed and
dissolved, filtered through a membrane filter with pore size of
0.22 .mu.m under pressure to obtain an image fixing component
R1.
TABLE-US-00004 Diethylene glycol 10.0 parts Calcium chloride
dihydrate 10.0 parts Acethylenol EH (from Kawaken Fine Chemical)
0.5 parts Ion-exchanged water rest
[Preparation of a Supplementary Liquid]
Next, a supplementary liquid including a resin and a surfactant was
prepared as described below.
(Preparation of a Supplementary Liquid S1)
Ingredients in the composition ratio shown below were mixed to
prepare a supplementary liquid S1.
TABLE-US-00005 Hexylene glycol 10.0 parts Ethylene glycol 5.0 parts
2-pyrrolidone 5.0 parts Polyvinylpyrrolidone (K-15; molecular
weight 10000) 5.0 parts Acetylenol EH (from Kawaken Fine Chemicals)
0.5 part Ion-exchanged water rest
Image formation was carried out using an image fixing component R1,
pigment inks K1, C1, M1 and Y1, and a supplementary liquid S1
prepared as described above.
The print head 18 for ejecting inks of each color and the print
head 19 for applying the supplementary liquid used in the present
example had recording density of 1200 dpi, and as a driving
condition frequency of driving was 10 kHz. The amount of ejection
of each dot from the head used was 4 pl.
First, after coating the transfer drum 1 with the image fixing
component R1 to thickness of about 1 .mu.m, pigment inks Y1, M1, C1
and K1 were sequentially applied with the ink-jet head 18 to form
ink images on the transfer drum 1.
In the occasion, the pigment inks of each color on the transfer
drum 1 were coagulated through reaction with the image fixing
component R1, and the ink images 20 formed on the transfer drum 1
were good images without beading. Coagulation occurred
instantaneously so that multiple applications of inks did not cause
such phenomena as beading and bleeding, and the ink images 20
formed on the transfer drum 1 were confirmed to have high
quality.
Next, the supplementary liquid S1 was ejected from the print head
19 for applying supplementary liquid, and applied to the high
quality images, i.e. the ink images 20, on the transfer drum 1.
Further, water which were main solvent were evaporated from the ink
images 20 on the transfer drum 1 by air blasting from the air knife
22 in the next step. Then, in the transfer portion 6 the ink images
20 on the transfer drum 1 were transferred to the recording media 9
fed by the transportation rollers 24a and 24b, and thus prints were
formed. Further, the prints were passed through the
transportation/fixing rollers 29a and 29b at a heating temperature
of 150.degree. C. to form fixed images. The finally obtained color
images were high quality images having good abrasion resistance
that prevents ink stain even rubbed immediately after discharge.
Thus, images without beading and bleeding, with ink images 20 on
the transfer drum 1 thoroughly transferred to the recording medium,
and having excellent abrasion resistance and water resistance were
obtained. The transfer drum 1 did not have any residual inks, and
the surface was easily cleaned. Further, high quality images could
be formed even when the above-mentioned steps were repeated.
The Second Embodiment
In the present embodiment, the supplementary liquid applying
portion 4 is arranged between the image fixing component coating
portion 2 and the ink applying portion 3, so that the supplementary
liquid 21 is applied to the transfer drum 1 before the inks of each
color are applied to the transfer drum 1 in the ink applying
portion 3.
FIG. 2 is a schematic sectional view of an image formation portion
of an ink-jet recording apparatus related to an embodiment of the
present invention.
In FIG. 2, since devices indicated by reference numerals 1-11 and
parts conforming them and a control portion (unshown) are same as
those in FIG. 1, description of them is abbreviated.
In the figure, the supplementary liquid applying portion 4 is
arranged between the image fixing component coating portion 2 and
the ink applying portion 3. Of the series of operations of the
ink-jet recording apparatus of the present embodiment, those that
are same as in the first embodiment will be abbreviated here, and
only those characteristic to the present embodiment will be
described below.
On receiving external image signals, an intermediate transfer body,
i.e. a transfer drum 1, is rotated, and an image fixing component
16 is coated on the transfer drum 1 in the image fixing component
coating portion 2. Next, a supplementary liquid is applied from a
print head 19 for applying supplementary liquid 21 to the transfer
drum 1, and then inks are ejected in an ink applying portion 3 to
form ink images 20 on the transfer drum 1. Then, through the
operations described with the first embodiment, the ink images 20
are transferred to recording media 9.
In the present embodiment, image fixing components, colored inks,
and supplementary liquids that can be used in the first embodiment
can also be used.
As described above, since an image fixing component 16 and a
supplementary liquid 21 are used in the present embodiment as in
the first embodiment, ink images 20 on the transfer drum 1 has high
cohesive force. Therefore, when the ink images 20 are transferred
to recording media 9, high quality images without beading and
bleeding, having good abrasion resistance that prevents ink stain
even if the images are rubbed immediately after output, can be
formed.
An example of the present embodiment using examples of the
above-mentioned image fixing components, colored inks, and
supplementary liquids is described below.
EXAMPLE 2
In the present example, images were formed using the image fixing
component R1, pigment inks K1, C1, M1 and Y1 and the supplementary
liquid S1 described in Example 1 were used to form images.
The print head 18 for ejecting inks of each color and the print
head 19 for applying the supplementary liquid used in the present
example had recording density of 1200 dpi, and as a driving
condition frequency of driving was 10 kHz. The amount of ejection
of each dot from the head used was 4 pl.
Immediately after coating the transfer drum 1 with the image fixing
component R1 to thickness of about 1 .mu.m, the supplementary
liquid S1 was ejected onto the transfer drum 1 from the print head
19 for applying supplementary liquid based on the logical sum
signal of the binary format image signals of each ink. Then,
pigment inks Y1, M1, C1 and K1 were ejected from the print heads
18a, 18b, 18c and 18d according to binary format signals of each
color to form ink-jet images on the transfer drum 1. As a result,
high quality coagulated ink images were formed on the transfer drum
1 like in the example 1. The image quality of the final prints is
good without beading and bleeding, and abrasion resistance was
improved due to existence of much resin layer on the surface of
images after transfer.
The Third Embodiment
The present embodiment is characterized by that the supplementary
liquid application means conforming the supplementary liquid
applying portion is a roller.
FIG. 3 is a schematic sectional view showing conformation of an
image forming portion of an ink-jet recording apparatus related to
an embodiment of the present invention.
In FIG. 3, since devices indicated by reference numerals 1-3 and
5-11 and parts conforming the same and a control portion (unshown)
are same as those in FIG. 1, description of them is abbreviated.
Here, only the part characteristic to the present embodiment, the
supplementary liquid applying portion 4, is explained.
In the figure, the supplementary liquid applying portion 4
comprises a supplementary liquid 21, a supplementary liquid storage
part 33, and supplementary liquid supply rollers 34a and 34b.
The supplementary liquid applying portion 4 coats the supplementary
liquid 21 in the supplementary liquid storage part 33 in the whole
image formable region on the transfer drum 1 including the ink
images 20.
In the figure, the supplementary liquid applying portion 4 is
positioned at down flow side of the ink applying portion 3 on the
transfer drum 1. The supplementary liquid 21 is coated on the ink
images 20 formed with two supplementary liquid supply rollers 34a
and 34b on the transfer drum 1. In this occasion, the supplementary
liquid supply roller 34a can be abutted to and detached from the
transfer drum 1 corresponding to image signals sent from the
control portion. Though highly wettable materials are preferable as
the supplementary liquid supply rollers 34a and 34b, porous or
surface concavo-convex materials such as materials like gravure
rolls can also be used. The supplementary liquid applying portion 4
is so conformed that it can be abutted to and detached from the
transfer drum 1 under the control of an unshown abutting/detaching
control device.
Although the supplementary liquid applying portion 4 is positioned
at down flow side of the ink applying portion 3 on the transfer
drum 1 in the present embodiment, it may also be positioned at up
flow side of the ink applying portion 3.
Of the series of operations of the ink-jet recording apparatus of
the present embodiment, those that are same as in the first
embodiment will be abbreviated here, and only those characteristic
to the present embodiment will be described below.
When ink images 20 are formed in accordance with external image
signals on the transfer drum 1 by means of the image fixing
component coating portion 2 and the ink applying portion 3, the
supplementary liquid supply roller 34a is abutted to the transfer
drum 1. Then, rotation of the supplementary liquid supply roller
34b allows the supplementary liquid 21 to be coated on the
supplementary liquid supply roller 34a through the supplementary
liquid supply roller 34b, and then the supplementary liquid 21 is
coated on the ink image 20 formed on the transfer drum 1. After the
supplementary liquid 21 is coated on the ink images 20 in one
rotation of the transfer drum 1, the supplementary liquid supply
roller 34a is detached from the transfer drum 1. Then, the ink
image 20 is transferred to recording media 9 through the operations
described in the first embodiment.
In the present embodiment, the image fixing components, the colored
inks and the supplementary liquids usable in the first embodiment
can also be used.
As described above, since an image fixing component 16 and a
supplementary liquid 21 are used in the present embodiment as in
the first embodiment, ink images 20 on the transfer drum 1 has high
cohesive force. Therefore, when the ink images 20 are transferred
to recording media 9, high quality images without beading and
bleeding, having good abrasion resistance that prevents ink stain
even if the images are rubbed immediately after output, can be
formed.
An example of the present embodiment using examples of the
above-mentioned image fixing components, colored inks, and
supplementary liquids is described below.
EXAMPLE 3
In the present example, images were formed using the image fixing
component R1, pigment inks K1, C1, M1 and Y1 described in example 1
and the supplementary liquid S2 described below were used to form
images.
(Preparation of a Supplementary Liquid S2)
Ingredients in the composition ratio shown below were mixed to
prepare a supplementary liquid S2.
TABLE-US-00006 Hexylene glycol 15.0 parts Ethylene glycol 15.0
parts Polyvinylpyrrolidone (K-90; molecular weight 360000) 10.0
parts Acetylenol EH (from Kawaken Fine Chemicals) 0.5 part
Ion-exchanged water rest
The print head 18 for ejecting inks of each color used in the
present example had recording density of 1200 dpi, and as a driving
condition frequency of driving was 10 kHz. The amount of ejection
of each dot from the head used was 4 pl.
After coating the transfer drum 1 with the image fixing component
R1 to thickness of about 1 .mu.m, pigment inks Y1, M1, C1 and K1
were ejected from the print heads 18a, 18b, 18c and 18d according
to external image signals, and ink images 20 were obtained on the
transfer drum 1.
Next, the supplementary liquid S2 was applied to whole area of the
transfer drum 1 by means of the supplementary liquid applying
portion 4. Then, most of the main solvent, i.e. water, on the
transfer drum 1 was evaporated by air blowing from the air knife 22
in the next step. After that, the whole image region including the
ink images 20 formed on the transfer drum 1 was transferred to the
recording media 9 fed by the transportation rollers 24a and 24b in
the transfer portion 6, and thus prints were formed. Further, the
prints were passed through the transportation/fixing rollers 29a
and 29b at a heating temperature of 150.degree. C. to form fixed
images. The finally obtained color images were high quality images
having good abrasion resistance that prevented ink stain even
rubbed immediately after output. Thus, images without beading and
bleeding, with ink images 20 on the transfer drum 1 thoroughly
transferred to the recording medium, and having excellent abrasion
resistance and water resistance, were obtained. Further, images
with gloss all over, in spite of irregularity of the surface of the
recording media 9, were formed.
The Fourth Embodiment
The present embodiment is characterized by that a supplementary
liquid application means conforming the supplementary liquid
applying portion is arranged at down flow side of the ink treatment
portion 5.
FIG. 5 is a schematic sectional view showing a conformation of the
image forming portion of an ink-jet recording apparatus in
accordance with an embodiment of the present invention. In FIG. 5,
since devices indicated by reference numerals 1-11 and parts
conforming them, and a control portion (unshown) are same as those
in FIG. 1, description of them is abbreviated.
In the same figure, the supplementary liquid applying portion 4 is
positioned at down flow side of the ink image treatment portion 5
on the transfer drum 1. The supplementary liquid 21 is coated on
the ink images 20 formed with two supplementary liquid supply
rollers 34a and 34b on the transfer drum 1. In this occasion, the
supplementary liquid supply roller 34a can be abutted to and
detached from the transfer drum 1 corresponding to image signals
sent from the control portion. The supplementary liquid applying
portion 4 is so conformed that it can be abutted to and detached
from the transfer drum 1 under the control of an unshown
abutting/detaching control device.
Of the series of operations of the ink-jet recording apparatus of
the present embodiment, those that are same as in the first
embodiment will be abbreviated here, and only those characteristic
to the present embodiment will be described below.
The ink images 20 are formed in accordance with external image
signals on the transfer drum 1 by means of the image fixing
component coating portion 2 and the ink applying portion 3. Next,
most of the main solvent, i.e. water, on the transfer drum 1 is
evaporated by air blowing from the air knife 22 of the ink image
treatment portion. Next, the supplementary liquid supply roller 34a
is abutted to the transfer drum 1. Then, rotation of the
supplementary liquid supply roller 34b allows the supplementary
liquid 21 to be coated on the supplementary liquid supply roller
34a through the supplementary liquid supply roller 34b, and then
the supplementary liquid 21 is coated on the ink image 20 formed on
the transfer drum 1. After the supplementary liquid 21 is coated on
the ink image 20 in one rotation of the transfer drum 1, the
supplementary liquid supply roller 34a is detached from the
transfer drum 1. Then, the ink image 20 is transferred to recording
media 9 through the operations described in the first
embodiment.
In the present embodiment, the image fixing components, the colored
inks and the supplementary liquids usable in the first embodiment
can also be used.
As described above, since an image fixing component 16 is used in
the present embodiment as in the first embodiment, ink images 20 on
the transfer drum 1 has high cohesive force. Therefore, when the
ink images 20 are transferred to recording media 9, high quality
images without beading and bleeding, having good abrasion
resistance that prevents ink stain even if the images are rubbed
immediately after output, can be formed.
An example of the present embodiment using examples of the
above-mentioned image fixing components, colored inks, and
supplementary liquids is described below.
EXAMPLE 4
In the present example, images were formed using the image fixing
component R1, pigment inks K1, C1, M1 and Y1 described in example 1
and the supplementary liquid S2 described below were used to form
images.
(Preparation of Supplementary Liquid S2)
Ingredients with ratios shown below were mixed to form a
supplementary liquid S2.
TABLE-US-00007 Hexylene glycol 15.0 parts Ethylene glycol 15.0
parts Polyvinylpyrrolidone (K-90; molecular weight 360000) 10.0
parts Acetylenol EH (from Kawaken Fine Chemicals) 0.5 part
Deionized water rest
The print head 18 for ejecting inks of each color used in the
present example had recording density of 1200 dpi, and as the
driving condition, frequency of driving was 10 kHz. The amount of
ejection of each dot from the head used was 4 pl.
First, after coating the transfer drum 1 with the image fixing
component R1 to thickness of about 1 .mu.m, pigment inks Y1, M1, C1
and K1 were sequentially ejected from the print heads 18a, 18b,
18c, 18d according to external image signals to form ink images on
the transfer drum 1.
Next, the main solvent, i.e. water, on the transfer drum 1 was
evaporated by air blasting from the air knife 22 in the ink image
treatment portion. Then, the supplementary liquid S2 was applied
all over the transfer drum 1 by the supplementary liquid applying
portion 4. In the transfer portion 6, the whole image region
including the ink images 20 formed on the transfer drum 1 was
transferred to the recording media 9 fed by the transportation
rollers 24a and 24b, and thus prints were formed. Further, the
prints were passed through the transportation/fixing rollers 29a
and 29b at a heating temperature of 150.degree. C. to form fixed
images. The finally obtained color images were high quality images
having good abrasion resistance that prevented ink stain even
rubbed immediately after output. Thus, images without beading and
bleeding, with ink images 20 on the transfer drum 1 thoroughly
transferred to the recording medium, and having excellent abrasion
resistance and water resistance, were obtained.
In the present embodiment, the supplementary liquid 21 is applied
after drying to implement transfer. Further, acceleration of drying
can be controlled by means of re-drying before transfer. This has a
further advantage that high speed recording can be implemented.
The Fifth Embodiment
In the first to forth embodiments, the supplementary liquid
applying portion is arranged at down side of the image fixing
component applying portion. However, the supplementary liquid
applying portion may be arranged at the up side of the image fixing
component applying portion.
The present invention has been described in detail with respect to
preferred embodiments, and it will now be apparent from the
foregoing to those skilled in the art that changes and
modifications may be made without departing from the invention in
its broader aspect, and it is the intention, therefore, in the
apparent claims to cover all such changes and modifications as fall
within the true spirit of the invention.
This application claims priority from Japanese Patent Application
Nos. 2003-391485 filed Nov. 20, 2003 and 2004-307229 filed Oct. 21,
2004 which are hereby incorporated by reference herein.
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